Grinding-machine.



J. BATH.

GRINDING MACHINE.

APPLICATION FILED run, 1909.

1 H l I l I I I I i X i I I I 1 I l 2 I l x J, n W 7 m U L f I 2 a. T J m m V W ru m QN EN I: 4 a

WITNESEEE J. BATH.

GRINDING MACHINE. APPLICATION FILED IEBJ, 1909.

1 036,545}. Patented Aug. 27, 1912.

9 SHEETS-SHEET 2.

WAFF

J. BATH.

GRINDING MACHINE. APPLIGATION'IILED FEB. 1, 1909 1,036,544. Patented Aug. 27, 1912.

I 9 SHEETS-SHEET 3. b I set I 9 1 I: I S \I. 1.. 1 lg $01 [I] [INTI o o a y In Q9 9 3 I I\ 2 1 I; a- J I a J I! I t 0 N .l l N] I I I m 0 i eo E a #3 00 I! 1 k b h 3 3 z\ l go N i mm W mg, I :8 3 I]! k I) I w r- 1 a L\ N It: 1 I," r N I II my I 1 Q R m l a 1 ll 0: 3 {D I III J. BATH.

GRINDING MACHINE.

APPLICATION FILED FEBJ, 1909,

1 ,O36,54 4. Patented Aug. 27, 1912.

\M M55555 ii/ NTE *fiwwmzwm 515M My J. BATE.

GRINDING MACHINE. APPLICATION FILED 533.1, 1909. 1,036,544, Patented Aug. 27, 1912.

9 BHEETB-E-HBET 5.

9B 171 lzga 11 4 7 11 mm 106 u 213 mun m will! M my 103 AWGSW llllllllfl J. BATH. GRINDING MAGHILE,

APPLICATION FILED rm. 1, 1909.

0' 9 SHEETS-SHEET 6.

. Patenfieii Aug.'27,1912.

Patented Aug. 27, 1912 9 SHEETS-SHEET 7.

BATH.

GRINDING MACHINE,

APPLIGATION FILED PEB.1, 1909.

GRINDING MACHINE.

APPLIUATION FILED IEB.1,1909

nrrnn s'rArns JOHN BATH, F FITCHIBURG, MASSACHUSETTS, ASSIGNDR T0 BATE-I GRINDER CO1:-

IANY, 0F FITCHBURG, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

To all whom it may comcm:

Be it known that I, JOHN BATH, ot Fitch burg, in the county of Worcester and State of hlassachusett s, have invented certain new and useful Improvements in Grinding-Machines, of which the following is a specii'n and ease of operating the machine also aug- 0 merited.

Clhe objects of this invention include among other things, to permit work of different characters to be performed at one time, toprovide a meansof stopping the on eration of the machine after the ivorl; has been ground down to apredetermined limit. regardless of the Wear which may have taken place in the meantime in the grinding wheel, to provide sliding holders tor the counter. shafts which furnish the driving power for the grinding Wheels, at the some time furnishing an additional means of adjustment for the driving belts, and to provide many other improvements in constructive detail and mode of operation, as will appear from the following specification and claims.

(if the accompanying drawings,-Fignre 1 represents a front elevation of my improved type of grinding machine. Fig. 2 represents a plan View of the same. Fig. 3 represented rear elevation. Fig. a repre sents anend elevation as seen from the left of Fig. 1. Fig. 5 represents an elevation on an enlarged scale, of the mechanism for moving the cross feed carriage. Fig. 6 represents a plan V w of the same, showing also the variable speed driving and reversing mechanism: for the Work table or bed. Fig. .7 represents a vertical sectional view illustrating the dog-controlled means for re versing the Work table feed. Fig. 8 represents a sectional plan View of the handle by which the Work table feed is manually con trolled. Fig. 9 represents an elevation of Specification of Letters Patent Tatm' 'tecl Aug, 2'2, 3 Application filed February 1, 1905.

Serial No. 475,421.

one of the spindle heads. Fig. 10 represents sectional view on line lG*l0 of Fig. 9. Fig. 11. represents a sectional detail view on an enlarged scale, of the adjusting device for the feed knoclvott shield. F 12 represents a vertical cross sectional view of one of the Work holders. 13 represents a plan view of the same. lrl'lGPlESQlilS a sectional view oi? one of the grinding Wheels and the supporting hearing therefor, the driving spindle being shown in elevation. Fig. 15 represents an elevation showing the relation of the grinding Wheel to the work when acting on a holloirworlr piece. Figs. 16 and 1? represent respectively, an elevation and a longitudinal .tion of a modified. form of grinder spindle hearing. Figs. ill and 19 are detail sectional views showing a device for retaining the truing' tool hold I permitting its displacement a d accurate return to position, the latter figure beingon an enlarged scale. Fig. 20 represents sew tional View showing a single Work holder adapted to hold one or more Work pieces oi the same or diiierent characters. showing; also how the machine may be adapted tor the en'iployment of a grinder bar supported at both ends. Figs. 2i and 22 represent modifications of 20, showing di Ways of supporting the 'nder bar or to diminish healing of the hearing.

The same reference characters indicate the same parts in all the ti res. I The machine compri a hose 1 on the on posits side of which rise columnar arms :2 and 8 which also branch odtwardlv from the base. Across the tops of these arn and united thereto extends a tubular arm or cross n'eo l which has a guideway to support sliding'ly the slides on v'hich are mounted the brackets and bearings carrying the grinder spindles. Between the arms 2 and 3 is a third arm which supports the beam or Web at intermediately. T his construction. as Will be evident. supplies the maximum of strength and rigidity. Between the hori zontal beam and the top of the base or lower bed or table which travels on such guides in the direction necessary to carry the work past the grinding wheels. which is approximately perpendicular to thefon Md and back feeding movement of the carriage.

Preferably the lower bed is made in two parts 11 and 11", one of which is driven by mechanism to be described, and the other of which is connected detachably to the former by means. such as a link 12, which may be disconnected for a purpose to appearhercinafter. On each of the parts of the lower bed is an upper bed or platen 13 centrally swiveled, by means of a pivot 14, to the lower bed. If desired, the lower bed may be nnide in one piece, and in this case there will be but one plat n 13 equal in length to the combined length of the two platens shown in Fig. 1. and pivoted in its center. The piroting of the upper bed or base en:

ables it or them to be slightly inclined so as.

to grind taper work.

The holder or holders for the work may be of various characters. In Fig. 1, two forms of work holders are shown. One of these is a sleeve 15 journaled in-a pivoted bracket 16 which is supported on the lefthand upper table or platen 13, while the other is a chuck 17 of common construction, having a bearing in a similar bracket 18 mounted upon the other bed or platen. The work carried by the holder 15 is a tube or sleeve 19 secured in the holder'by set screws 90. while the work adapted to be secured in the other holder consists of collars or such short pieces, designated by the numeral -?1. The work is constantly rotated while bring acted upon. suitable means for accomplishing this result consisting of pulleys22 I secured to the shafts of the work holders and driven by means such as belts 24 25.

The grinding wheels to; the work pieces a c represented at 26 and QT respectively, hr 'lornu of which is mounted in a tubular b at-inc; bracket which prrriccts longitudinally oi the bed and of the direction of ravcl of the work from its suppcrtii'ig 1w ins. A simi ar bearing, lllzWllGt. but per n'uss blr ot a different. size and designated i y supports and proyides a bea no for p udic r the set-oral grinding" wheel 27. Q

l uspindle for this grinding wheel pa thron -h bearings 50 and 31 which are seurrd to forwardly and rcarwaidl adiusb able Sl1dko 32 and 9 as in my pending ap pli ation above referred to. The other -'of the slide out of its correct rindcr spindle is similarly mounted in bearings 34 35 attached to similar slides fall; 37. Each pair of slides and with them the la-ari||gs.'a1'e adjustable bacltaud forth by means of a screw 38 engagim, a nut 51'.) held in a yoke 40 which bridges the slides and passes through slots therein. being secured to the guidcways 41 on which the. slides travel. The forward end of the screw has a bearing in a plate 4-2 secured to both the twarings of the set. The bearings for each grinder spindle constitute a spindle head, and both spindle heads are alike. That for the right-hand spindle is mounted upon a slide 43 which travels upon the guidcway 44, forming the front face of. the horizontal cross web or beam, the brackets 45 which carry the. guides 41 for the spindle head slides hein g adjustably secured in a slot 46 of such slide 4-3. As appears from Figs. 4 and 10. the guideway 4.4 has the form of the. usual dove-tail or undercut guide. but occupies a position at right angles to that usually assumed by such guides. so that the broadest face thereof is vertical, and oneof its edges is directly above the other. This upper edge extends horizontally and guides the slide, the latter being caused by its weight to bear against such edge. Thereby displacement ath of move ment. is impossible without the exercise of suflicient force upwardly to overcome its weight, which, under ordinary working con ditions, would never be applied. The guideways for the other spindle head are mounted on similar brackets 48 which are adjustable in a longitudinal slot 49 of a slide 50 which rests on and similarly grasps the guideway at the left-hand end of the cross beam. Each slide has a lip 51 embracing the lower edge of the guideway and containing a plate 52 which may be clamped against the guidcway by screws 53 so as tolock the slide in any position. v

The lefthand slide has a set of rack teeth 54 on its lower edge by which force may be imparted to move it along its guide. The means for applying such force is a hand wheel 55 at the front of the machine, and at the left of the crossfeed carriage. This band wheel is mounted on the end of a shaft 56 iournaled in a bearing 57 at the end of an arm which depends from the cross beam near its left-hand end and extends to the front ot the machine. The rear end of the shaft 56 carries a pinion 59, and through the medi nn o gears 30 (31 and 0?, drives a pinion (13 which n'icsh s with the rack. This gr-anusenables the operator of the machine to shift the slide and the left-hand grindini! wheel while standing! at the front of the ma chine in position to attend to the other mechanisms thereof.

Each spindle is continuously rotated while in operation. The lcft-hand spindle and .nlillillillllllmaimr i.

tool are driven by a bell (H which passes ov r a pulley 05 secured to the spindle bceen its bearings, and over :1 driving drum 136 on a cmmtershaft having its bearings in 5 brackets 67 07'. The other grinding wheel is driven by a pulley 68, belt 69 and pulley 70 on u second countcrsha-ft 71 carried in brackets 72. Each countershaft and the pair of brackets which supports it is independent of the other, but the brackets of each pair are connected by webs 73 and 74-. The former of these is supported by arms 75 secured to and extending rearwzirdly from the beam .1; while the other ,countershaft is holder is mounted upon similar arms or brackets 76.

lb are preferably cast integral with the beam 4 and have undercut slots 77 in which contained the heads of bolts l8 by which go the countersheft holders are clamped to the brackets. Each holder may be adjusted outwardly by a screw 79 passing through stud 80 formed upon the beam a and bearing "inst the web of the holder. The-two countershufts are separate and so also are their holders, so that each is capable of indegene-lent adjustment. to maintain the requiit 'tension of the belts 04 and 09, respectively. The belt 64; is subject to greater so stretch than the other belt, for the reason with the back and forth movementsof the slide in the ordinary conditions of use, while the belt 69 travels ordinarily in one plane. lli'i i slide which carries the left-blind grinding wheel is moved back and forth whenever finished work is removed from the machine and new work substituted, and also other times it is necessary to displace} the tool for taking measurements. By moving the grinding wheel 26 for enough to the left, only the leit hund work piece may be ed and removed from its holder, but a whole may be m ovecl far enough to clear the right-hand work piece grinder. Thus frequent adjustthe right-hand grinder are uunect lllQ on the other hand, it is necesoften to more the left-hand grinder cl: and forth. If desired. this capability is left. hand grinding wheel to be moved 1 vily while at the some time being ierl, he utilize-cl in the regul- 1 operation, either in conjunction TE lo. gitudinal-truvel of the work, or work is held stationary. By rothe hand wheel at syunilorm rate,

"b' vieel may bemoved longitudinally back i sources the fees of the work, srd

the wheel or the work, or both, y o transversely between the grinding These arms or brackets 75 and ti shit is caused to travel along the drum 06' tershaft 71, so that the griiider 27 may be put in dillcrentpositions. .For'this purpose the countershaft'i'l is shown as having not only the pulley but also'u second pulley 81, and other pulleys of similar character 70 may be mounted upon this countershaft if desired, to permit still further adjustments of the grinderr These pulleys are detachably connected with the shaft, being loosely mounted thereon and adapted to be clamped by friction binding means, such for instance as the cone friction on the pulley and a nut secured to the shaft and adapted to be clamped against the friction cone. The countershafts are provided with step pulleys 82 and 83 (Fig. 2) respectively, by which they may be driven by belting from the main source of power.

The countershaft 71 not only drives the grinder 27 rotatively, but also furnishes the power by which the longitudinal reciproeating movements of the bed and the work holders are effected. On the shaft is a pulley 84 from which a belt 85 conveys power to a pulley 80 on a shaft beneath, this shaft being contained in a bearing 87 secured to the standard 6. (in the shaft is a pinion 88 meshing with a gear 89 on a shaft 90, which, through a system of variable-speed and reverse gearing, drives a 91 (see Fig. 6) in mesh with a rack 92 (Fig. 4). This gear, train is shown in Fig. 6, and consists of a series of gears 93 of graduated diameters secured to the shaft 90 in. mesh with complemental gears 94 loosely mounted upon a parallel shaft 95, which shaft drives a third shaft 90 through pinions 97 and 98. Shaft 96 has secured to it it worm 99 with which meshes a worm wheel 100, said worm wheel being positively connected with a bevel pinion 101 in mesh with two bevel pinions 102 103 respectively, which itdrives simultaneously in opposite directions. These pinions are loosel mounted upon asliatt 104L- upon which the gear 91 before-mentioned is secured. Each of the pinio-ns 102 103 carries a clutch element 105 adapted to be engaged with complements]. clutch elements on the opposite ends of a sleeve 106 which is slidingly mounted upon theshat't 104, and is caused to have simultaneous rotation therewith by a pin 10? passing through the shaft and sleeve. A rod 108 passes longitudinallythrough the shaft 104- and engages said pin 120 so 'tlla-l when reciprocsted, itwill move the clutch sleeve 106 into or out of engagement with either of the clutch elements 105. "The rod is moved by a bell crank 109 pivoted to the front of the machine, and having on one its a roll. 110 engaged between a collar 111 secured to the rod.

The outer end of the bell crank carries a bundle 112 by which it may be manipulated,

and is also connected through an interl3? mediate block 113 see Fig. 7) with a slide 1114 which is engaged with a trip lever 115 pivotally mounted at one end and engaged. with the slide by a pin on which is a roll 116 entering a notch in the slide. \Vhen the bell crank is in the position shown in Fig. 6, the forward pinion 103 is connected with the shaftand the bed is moved toward the left, while when the bell crank is moved to its extreme left-hand position, the rear pinion 10) made fast to the shaft and the bed is driven toward. the right. In the intermediate position of the bell crank, the clutch is midway between both pinions and out of engagement with both, so that the bed is not driven in either direction. The handle 1152 provides for a manual reversal and disconnection of the table drive while an automatic reversal is effected by means of dogs carried by the lower bed or table.

The dogs consist each of a screw 11? threaded into a pivoted holder 118 which is pivotally mounted on a pin 119 passing through ears 120 on a. block 191. which is slidingly mounted on the front edge of the reciprocating lower bed or table. This table and each of the parts of which it is composed has a slot 1;.2. extending its entire length, in which is held the head of a. stud 122} (Fig '12) which passes through the block 191 and by m fttllt-J of clamping nuts 124, adjustably holds the latter in any position. \Vhen the pivoted holder 11S swung out int-o the horizontal position, shown in Figs. 12 and 1 the dog travels in a path in which lies the trip lever 1.15. At least two dogs are employed in the ordinary op oration of the machine, so that the lever is alternately bngaged and moved in opposite. directions by them, thereby reversing the drive in the manner above described. The location of the dogs of course determines the point at which the reversal takes place and may be varied according to the character of the work being done.

Preferably I employ more than one pair of dogs. and in Figs. 1 and 2 of the draw-- ings. I have shown two pairs. any two of which may be used for effecting reversals or for stopping the machine. When either of the endmost dogs is to be used, one or both of the intermediate ones is swung upward about its pivot. so as to clear the stop lever or trigger ltfi, and therefore to be inoperative. The use of more than two dogs is of great advantage in grinding pieces hay' steps. that is. portions of ters. for the dogs may l:e wet in posit'iorfor effecting: reversal at the points where the different steps occur.

ditl'ercnt diamc- 1 That is. one pair of 1 dogs will be set for enabling; the machine to grind the part of the work whivh hroject's the farthest another dog r pair thereof may be set for the next step of the work, and so ointherebeingga d gz'nlapted to 1 reverse the work when each step thereof is at the grinding wheel, and when the grinding shifts from one step to another, the dog previously used may be rendered inoperative by simply swinging i "p .bout its pivot, and another dog made operative, without el ringing the adjustment of any of the dogs. This insures uniformity of work, for one setting of the dogs sntlicient for an entire lot, and every piece of the lot will have 1ts steps ground to exactly the same length. If only one pair of dogs were used in grinding stepped work, they would have to be re-adjusted for each new piece, and the consequent opportunity for error might result in lack of uniformity in the pieces of a lot, and would possibly spoil some of them. Another use of the plurality of dogs is to enable the machine to be automatically stopped when the work has been withdrawn from the grinder to a more remote point than that at which it is usually reversed. That is. a pair of the dogs is set so as to effect reversal when each end of the length or portion of the work to be ground reaches the point of reversal, and then a third dog at a different position is set so as to stop the feed autonnitically after the work has been removed to a. more remote distance from the grinder. it being understood that; before the third dog l'ieeomes operative, one of the reversing pair is swung up out of the way of the trip. To permit this disconnection of the feed. the bell. crank 109 is constructed so that it; may be automatically stopped in mid-position, with the clutch 106 disconnected from both pinions 103. For this purpose the handle 112 is provided with looking pins 125 (see Fig. 8') which are adapted. to enter holes 1'26 in an apron which projects from the front of the machine franie. This handle is movable endwise on the end of the bell crank and carries on its inner end a flange 12'? on which the pins 125 are mounted. There is a spring 128 inside the handle which bears against a shoulder 129 thereof and at. its other end bears against: the head 130 of a stud 131 which. is screwed into the forwardly projecting arm of the bell crank. A slot 132 which is offset at one end and a pin 13?] enable the handle to be held in its outer position against the force of the sprirnr. When the pin in the straight part of the slot, the pins 135 are in line with the holes 1226 and the spring: presses the handle rearward, tending to force these pins into the h'des. ta'iseqnently as soon as the hell cra k .irrives at its mid-position, the pins ant-apatically slip into the holes and the feed i--' disconnected. ln order to connect the t'r-cd again. the handle is drawn out and turn d r--o as to bring," the pin li -1G into the oti'set part. of the slot. whereuifmn the pins 12 1 re out of line with the holes .26 and are a she ftosses-e away from them. The bell crank can then be swung in either direction. When the handiev is released, its flange 127 pressed against he. apron butthe pins 125 do not enter the holes 126 until the bell crank has been moved into mid-position. but in this position pins 125 are engaged in the complemental holes, and movement of the bell crank in either direction prevented.

The reciprocation of the worlecarrying beds effected. at any desired speed by making any one ofthe loose gears 9 1 which is necessary-to secure-that speed, fast to the Any suitable means may be used for this purpose, such as a rod 3 1 traveling through a central bore-of the shaft 95 and carrying a key (notshown),adapted to enter keyways in the hubs of the gears. A lever 136 l ving a handle by which itmay be lllllill dated is"provided for shifting the rod 134. This lever has a pivotally mounted tooth 13'? contained between two collars 138 on the rod 134, and is itself pivoted to a stud it swings over a segment M and has locking pin adapted to enter any one of the holes 11 2 of the segment, these holes being equal ii 1 number to the gears M and locking stud vnenever the key is in register with a gear. Stop pins limit the swing of the lever in each direction. A hand drive for reciprocating one beds is also provided. This consists of hand Wheel l-l l driving a gear 145 iii-mesh with the rack lhe gear 1&5 a shaft 1&6 separate from the shaft of the hand wheel, but driven by the latter thronghthe train'of gears 14-7 14:8 1&9 150 she cross feed of the carriage for feeding the work between cute is effected by a feed screw 151 mounted on the cross feed car positioned so as to receive the riage 7 and-engaging stirred nut- 153. This feed screw may be tnrned manually by a wheel it is else moved gradually antomatica-lly by the reversing mechanism.

The slide 11% has a cam projection with bevel i nceson both sides, whicl vhen moved in ei her direction, a roll pivoted to the end of a. plnnger 1 36, said orineily held npvn rd by a spring .s lower passes from a sleeve i1 gositicn toengage the end of a lever 1519 pivoted at 160 to a bracket 1&1. cerries pivoted upon it a pawl 162, the 163 of which engages the teeth of a ratchet wheel-16 which drives the feed screw 151 through a' gear train composed of pinions 165, and. 167, the first of thee slicing we i to the ratchetwheel and the last to the sc ew. At each reciprocation off the car a the plunger is de pressed, anr. the pawl 161 moved downward 2': feed screw a still smaller amount. The

pawl and its lever are returned bya spring 1% contained in a sleeve 16) formed upon the bracket 161 and pressing upward upon a plunger 170 which bears against the under side of the lover. The thrust of the spring is taken by an adjustable abutment 171 threaded into the lower end of sleeve 16$). The pawl is held yieldingly against. the face of the ratchet wheel by a short arm or tooth 172 pressed upon by a spring-pressed plunger 1725 held in a sleeve 17% formed. on the lever 159. The head of the said plunger has a notch 175 into which the tooth or short arm 172. may be moved, and when so moved, the toe of the pawl is held away from the ratchet wheel and retained by the walls of the.notch.

lVhen the carriage is to be fed by hand,

thewpawl and ratchet feed is disconnected.

either by swinging the pawl away from the ratchet or by disengaging the pinion 16G from' the gear 167. To permit of this last disengagement, the pinion 166 is hung in a holder 176 which is pivoted coaxially with the ratchet 164; and gear 165. It projects beyond the circumference of the ratchetand has a shortslot 177 through which extends a screw clatnp 178 by which it may be locked so as to hold the pinion 166 in mesh with the gear 167, or entirely out of contact therewith. l.

The machine is adapted for an automatic disconnection of the feed when the grinding so i has proceeded far enough. The means for so disconnecting the feed is a shield 179 carried by a disk 180 mounted so as to swlng upon the shaft 181 to which the ratchet is' ables the pinion 182 to be turned, thereby.

moving the shieldinto any position desired over the face of thera'tchet. Accidental displacement of the shield is prevented by means of a friction disk 189 between the hub of the handle 187 and the disk 180. The amount of frictional resistancewhich this disk or washer interposes is governed by a nut 190 in the handle 187 which takes over a screw projection 191 on the stud 183. This not bears against an internal shoulder in the handle and may be adjusted to cause the handle to press with more or less force against the friction washer. This means for adjusting the feed knock-off shield I consider one of the important features of the present invention.

There is automatic means for adjusting thespindle heads so as to effect an automatic feedof the grinding wheels as well as of the work, this automatic feed being substantially the same as described in my pending application referred to, with the addition of features as to means for holding the feed pawl out of engagement, and of adjusting the feed knock-ofi' shield, which are the same as just described in connection .with the carriage feed. The ratchet 192 on the feed screw 38, pawl 193, bar 194 having the twosided cam 195, and the standards 196 on the bed for reciprocating the bar 194 are sub stantially the same as shown in said application. The lever 197 upon which the pawl 193 is pivotally mounted, has, however, a sleeve 198 in which is a plunger 19S) pressed upward by a spring contained in the sleeve between the plunger and an abutment 200,

said plunger being held againstthe short pointed arm or tooth 201 on the pawl. The head of this plunger also has a notch 202 by which to retain the pawl separated from the ratchet 192. The" toe 203 of the pawl is a beveled block or rod set into the pawl and held by a set screw 204. The lever 197 is 'pivoted between its ends at 205 and norn. ll pressed upward by a spring 206 w icli acts through a plunger 207. A screw 208 bearing under the arm 209 of lever 197 enables the pawl to be lowered, and thereby the movement imparted thereto by the cam 195 to be varied. Projecting over the ratchet is a shield similar in all respects as to its construction, mounting and manner of adjustment to that already described in con ncct-ion with the feed for the work-holding carriage, so that further detailed description thereotis unnecessary.

The construction of either grinding wheel spindle and its bearing is illustrated in detail in Fig. 14. For convenience it may be ssumed that the one here illustrated is the tt-hand wheel 26 and the bearing 28. This hearing has a flange 210 and an annular rib 211. with bolt holes 212 by which it may be secured to the spindle head. The spindle to which the wheel is directly secured is designated by 213 and is held in bearing boxes or bushings 214 and set into opposite ends of the sleeve or tubular bracket 2h. The spindle 213 is separate from the main spindle 216 to which the driving belt 64 imparts its power, and is engaged therewith by a rib 217 on one contained in a slot of the other. The bushing 215 is tapered and is held in close. engagement with a correspondingly internally tapered bore of the hearing by screw threads 21 T on the inner end of the bushing. Dust and grit are prc vented from working in between the spindle and bushing by means of a dust lock consisting of a collar 218 fitting over the reduced outer end of the bushing and a disk 219 fitting over the end- 220 of the spindle, which is reduced in diameter, and also in close engagement with the. face of the collar 218 and the end of the bushing. An annula'r rib 221 projects from the face of the disk 219 into a corres ondingly located and formed groove in t e adjacent face of the collar, and the latter has a peripheral rib 222 overlying the rib 221. A clamp nut 223 is threaded on the end of the grinder spindle and clamps the grinding wheel against the disk 219, holding the latter closely enough against the collar 218 and end of the bush ing 215 to leave the least possible space for particles dislodged from the work and wheel 40 work between them and into the bearing of the spindle. The nut has a sleeve or hub 224 taking over the part 220 of the spindle and fitting the bore of the grinding wheel.

The collar 218 is secured to the bushing by means of pins 225, so that the collar is prevented from rotating on the bushing and serves as a means to tu-rp the latter for screwing it more or less into or out of the hearing. A lock nut/226 is threaded on the outer end of the bearing and engages the collar 218, thereby holding the bushing in any adjustment and reveir't-ing it from being turned by the riction of the disk against it.

A modified tom. of spindle beariur is shown in Figl 17, in which the tubular hearing or bracket 28 is practically the same as the sleeve previously described, except that its bore is tapered from end to end. and there is a single bearing box or bushing 227 which is inserted into the sleeve from the end' of the latter which is attached to the spindle head, and is reduced in diameter gradually toward the outer end. This box is slotted at one side. having a longitudinal ezlot or groove 228 extending from its outer periphery to the bore in which the spindle is contained, which slot is provided so that ,the bushing may be crowded more or less tightly around the spindle to take up wear. A flange 229 is formed on the end of the bushing and screws 230 extend through the same into threaded engagement with the body of the tubular bracket, in order to force the bushing into the bracket. The engagement of the tapered exterior surface of the bushing with the tapered bore of the bracket crowds the walls of the slot 228 toward each other and so reduces the diameter of the bore in which the spindle has its bearing, thereby enabling the bearing to fit the spindle exactly and prevent side'shake.

)ne ofl'he important featuresof my invention is the construction of the work holders, or rather the brackets in which the rotating work-holding elements 15 and 17 have their bearings. The brackets 16 and 18 are the same in construction and a description of one will suflice for both. In Figs. 12 and 13 one of these brackets is shown in detail. It consists of a base 235 which is set upon the pivoted upper bed 13 and is guided thereon by a rib 236 and stud 237 the head of which is contained in an inverted T-shaped ltmgitudinal slot of the. bed. A tubular post 238 rises from the center of the base 135 and contains the headed stud. The main portion or ii ad lti of the bracket has a bore which receives the tubular post 2 h. and has a peripheral downwardly extending anmdar rib or tlange 3231) whieh surrounds a circular table on the top of the base 2:35. The bracket I is thus nun,"- able gnigularly about a vertical axis to permit adjustment of ill. axis ot the work at a slant with respect to the travel of the bed and grinding wheel. .'lhiseangularl v ad justable part of the b'aeket: contains the bearing 240 in which the shaft or stud 241 of the work holder is held. The bracket is locked in its various angular positions by a nut 2&2 threaded upon the exterior ot the tubular post 231k and contained in a surrounding annular recess in the braeket. This nut is independent of the headed stud 237, which is independently elamped so as to secure the bracket in an) position longitudinally of the bed, by means of a not 2423 hearing against the end oi the post 238. Accordingly either the longitudinal or angular adjustment of the bracket may be made independently without disturbing the other adjustment. ln order to locate the bracket with the axis of the work holder exactly in line with the direction of move ment of the bed, a pin ll-l is provided, which pin passes through the bracket and extends into a tapered hole 243 in the base 235. This enables the axis of the work holder to he brought into line without measurements or adjustments, and therefore without loss of time. It t'lesired. other holes located so as to receive the pin when the bracket is at definite angles of adjustment may be provided, so that. standard tapers may be ground in the work without, loss of time in making theauljustments.

The bearing is taken up and caused to embrace the stud ill-l without looseness, by

means of bolts Q-lttpassing through lips 247 248 on the splitbearing. The bolt is threaded into the lip .248 and has a surrounding sleeve 24$) pinned to it bearing against a -\\'car-resisting nut 250 which i screwed into the lip 24.7 around the bolt], and is secured by-a set. screw 251.

On top of the bearing bracket is secured a bracket 2.33 having a split sleeve 254 in which is clamped a shaftcarrying a truing tool .256. This truing "tool is a. threaded bolt. engaged with con'iplemental screw threads in the interior of a transverse hole made near't-he end of the shaft 2.35, and in the end of the bolt 25o is secured a diamond holder 257 having set in its outer end a diamond 258 or any other hard substance capable of cutting away the surface of the grinding wheel. T\hc shaft 5255 is of such a length that it extends beyond the end of the work and the truing tool projects toward the grinding wheel over the work in .such a pisiticn as to true oil the face of the wheel after each cut and maintain its surface true and in condition for grinding. The shall :55 is of such a diameter as to he very rigid, and is rigidly held in the split sleeve 35% by means ot" a bolt 259 which draws the sides oi the sleeve into clamping engagement with the shalft Also the end the shaft which is provided with the (71 threaded hole to contain the diamond holder is split. and the sides of the hole are drawn into gripping engagement with the luzlt by means of a screw 260 which draws the divided members of the end together. This construction provides an extre.'u:-'ly rigid means of support for the truing;- it so that the same is prevented from chatter ing and caused to face lift the grinding wheel smoothly. Furthermore, the taut that the t ruing tool is mounted in the e l t ot a horizontal rotatable shat't enables it to be turned sothat it will be, exactly radial to the wheel as the work fed and the grindmg progresses.

I propose to provide the grooves ltd, and to form in the bearing therefor a pocket or recess opening into the bore of the bearing sleeve and contain ing a hall 2G3. The inner end of the rec in which the ball is contained has a lip pr venting escape of the ball into the interior of the bearing, and the latter is pres. against the lip by a spring 26% contained in the recess and engaging a screw abutment "265 threaded into the outer end of the re ccss. The spring, presses the ball so that it enters any one of the grooves in the shaft, and thereby holds the shaft so that not be moved longitudinally except by the expenditure of considerable force, but it may be turned rotarily with comparative ease. The grooves and ball enable'the d mond holder to he. swung out of the way when work is being removed from and put into the wo'rl: holder, and then they en: ble the truing "tool to be brought. back into its former position Without re-adjustnnait. For work diil'erent lengths the shaft may be moved endwise until different grooves are brought intocngagement with the bait.

'It is. possible by slightly modifying the machine to enable one piece of Work to be simultaneously ground to diticrent diameters by two grinding Wheels extending toward the work from opposite ends. tVhcn werk of this character is;done. a single work holder capable of holding a piece with its bore open from end to end is used. F-iaich a holder is illustrated in Fig. Qt). The holder here is a sleeve 266 contained in bean ings 2&7 and 368 formed in brackets 2th) and lit] is held against end-shake by collars 272 which are secured externally upon it outside of the bearin s 9.67 and 268. Inside the.

work holder-t e work piece is secured. by clamping jaws or screws. Not only a single piece of work, but also separate pieces of the same or difi'eren't sizes or characters may be independently mounted in the work holder 266 and simultaneously acted upon by the two grinding Wheels. it will be noted that the. work piece or pieces are in engagement "with both wheels simultaneously during part of the time, and that the same movements of the work holder or holders in each case cause the work to travel .back and forth in engagementwith both wheels.

times bot-h tools are simultaneously in action. I

The arrangement (if two tools acting on a single piece, enables the interior surfaces when portions thereof are of different .dianr eters, to be made truly co-axial, and is an advance in the artof grinding over pre-, vious machines which permitted only a por tion of one diameter to be ground at any one time.

The necessary relative travel between the work and grinding wheel in order to bring the tool along the entire length of the surface to be ground can be effected by moving the grinding wheel longitudinally of its axis while the worlcholder remains in a stationary position. This movement is efiected by the hand wheel 55, and in plaeeof the :iutonmtic reveising mechanism for stopping the movement of the too] in this direction when the end of the surface tobe round reached, I provide a step 273' which is clamped upon the guideway 4st which supports the slides holding the spindle heads. This step is adjustable and may be placed so as to arrest the movement of the slide when. the wheel has been. carried. far enough into the work. For work pieqas which have a plurality oi internal mops, 1- pro as: to provide the stop with a number of e ements oi diiierent lengths which. may be adjusted in accordance with the locations of the steps so that the grinder may be arrested when it has penetrated into the work as pr as each of the steps. v The construction of the bearing bracket 28 previously described furnishes a means by which a grinding machine having a grinder spindle supported at both ends, as illustrated in my preceding application Serial No. 385,007, filed Julv 1907, may be converted into a two-grinder machine, such as forms the subject-matter of the present ap plication'. In the machine of the said application, as well as in the present machine, the grinder spindle is rotatably mounted in two tapered bearing boxes 275 between which is located the pulley 68 for driving the spindle. A bar rigidly held in similar bearing boxes and projecting toward the grinder spindle is employed to support the end of an arbor held in the grinder spindle on which the grinding wheel is mounted. When the supported spindle is replaced by two grinding wheels, the massive bar is removed, the clamping boxes in which the same is contained are taken out and replaced by others having bearings for a spindle, and a spindle having a driving pulley upon it is placed in these bearing boxes. A tubular bearing bracket isthen clamped to the spin dle head over the end of one of the boxes and projects toward the grinding wheel, supporting and bracing the projecting part of the spindle.

By the present invention I have devised a type of tubular spindle support which serves both to support an independent spindle passing through it and driven b a shaft contained in the bearing adjacent w ich said sleeve is supported, and also to support the end of a shaft or arbor bearing a grinding wheel, and driven from the remote spindle supported in the other set of boxes. In this connection I have invented also an improved form of grinder holder which may be readily disconnected from the spindle by which it is rotated. Fig. 20 illustrates the construction and arrangement by which independently driven spindles carrying two grinding wheels may be substituted for and replaced by a grinding wheel holder supported at both ends and carrying one grinding wheel. In this arrangement the rightdiand spindle 21.6 is the driver and the bearing sleeve 28 contains no spindle but simply an internally tapered bushing 215 which provides a bean ing for the shaftseclion or arbor on which the grinding wheel is mounted, and a spring 276 which yieldingly presses said bushing outward. The spindle here terminates just outside the inner bearin box 275, and has upon it a flange 277 whici may be contained within the cavity formed in the head 210 of the right-hand tubular bearingfl), which tu ularbear is similar in construction to the ing shown in Fig. 14. This bearing is here removed, leaving the head 277 exposed. The grinding wheel 26" mounted upon a shaft section 278 or arbor of sufficient diameter to be-rigid, anti is'clamped between a fixed collar 279 and an adjustable collar 280. This shaft section has on one end a short stud 281 which enters a complcniental socketin the end of the spindle, and it also has a collar or tlange 282 through which screws 288 are passed and are threaded into tapped holes in the head or flange 27?, for the purpose of communicating rotation from the spindle to the shaft. The tapered stud has so abrupt a taper that it will not bind in the spindle, and is provided simply for centering the shaft section 278 with respect to the spindle. The other end of this shaft section has a )rojection 284 entering the bushing 215*. "his latter bushing need not be internally tapered, but may be exactly like the bushing 215, in which case the same tubular bracket 28 may be used for both purposes, but I find it more convenient to have separate brackets for the two classes of work, as it is easier to remove oneland substitute the other than it is to remove the grinding wheel 26 and spindle section 213 in preparation for receiving the stud of the shaft section 278. The bushing 215 is preferably arranged so that it may rotate within the sleeve 28, and the stud 284 of the grinder spindle or arbor has one or more laterally projecting pins 291 which enter-notches in the end of the bushingand cause the same to turn with the arbor. These pins may be omitted if desired, and the bushing caused to turn by its frictional engagement with the stud. In any event, the support for the end of the arbor is capable of rotatin and the arbor is thus supported at its on s by rotating hearings or supports, the righthand support being the spindle section 216 which is driven. This capacity of the arbor bearing to revolve enables the arbor to revolve true and without heating in its hearing if it. should be slightly sprung by the action of.the clamping nut 280, or from other causes. The stud. 284 is short so that itmay act to a certain extent as a swivel joint and allow the arbor to accommodate it self in the bearings without causing the bearings to heat by an imperfect alinement' of the arbor. By thus mounting the grinder arbor with a'short connection in a revolving bearing bushing, the arbor. may be held rigidly against end movement, and at the same time be permitted to revolve at high speed withoutheating or grinding the bearing, regardless of whether or not it is relatively straight or in actual alinement. Another advantage of having the bushing revoluble is that whereas dustand grit might work in between the arbor stud 284 and the bushing, it cannot get. between the bushing and the inner surface of sleeve 28, because this bearing surface is protected by a cap.

292 which extends over the ends of the sleeve and bearing and is perforated to receive the stud 284. This cap has slots to permit pas sage of the pins 291 when the stud 284 is inserted and removed. 13y turning the hand wheel 55 and moving the slide .30 backward, the arbor 248 may be removed and another one of any diameter or length with a coarser or finer wheel, according to the character of the work operated upon, may be substituted. When the single wheel 26 is to be removed, the slide 50 carrying the left-hand spindle heads and tubular bracket is backed oit' clear of the shaft section and the latter by a slight movement endwise is clear of the spindle 216. As the taper of the stud 281 is sharp,

the latter is not wedged in the spindle, but

parts easily therefrom. The machine may then be made into a two-grinder machine by substitutnig tubular brackets, such shown in Fig. 14, upon the inner ends of ble of securing the same results is shown in Fig. 21. The arbor, grinding wheel, hearing sleeve or bracket and stud on the arbor which enters the bracket, are designated by the same numerals as before. The bearing for the stud 284 is acylinder 215 which revolves in a sleeve 293 contained within the bracket 28 and held by a set-screw On v 293 so as to prevent removal of the cylinder from the tubular bracket. The connection between the arbor and the right-hand spindle section 216. is made with a tapered head 299 on the projecting end of-the spindle section which enters a socket 300 in the end of the arbor and has a threaded stud 301 screwed into a tapped hole in the arbor. This connection supports the arbor and at the same time transmits rotation thereto.

Another modification is shown in Fig. 22, in which the stud 284 of the grinder arbor revolves in the bearing 215, which inturn is positively driven by the spindle section 216 in the left-hand head. The bearing bushing has a short stud-shaft 302 having a tongue-and-slot connection with the spindle section 216 similar to that illustrated in F 14. A nut 303 is screwed on the stud shaft. in the enlarged. head. of the bearing bracket: and prevents removal of the bush-- ing therefrom. The arbor stud 284- is not onnected with the but :ng, but is free to rotate therein and the latter is also rotated by "the spindle sect-ion 216.. This enables the "bar and bearing bushing to be rotated at erent speeds, the arbor having a greater city than the bu hing so that there will not be any excessive friction. grid the grinding wheel may be driven at as high speedas desired Without, heating in its bearing. This enables the necessary rigid support to be given to the left-hand end of; the arbor without heating. The connection of the right-hand arbor with the driving spindle section 216 at the right is made through a long tapered stud 304 on the spindle section, which engages in the arbor with a conncction similar to that of a twist drill. A trmisverse aperture 304 is made in the arbor so that it may be disengaged from the spindle by driving a tapered pin through the aperture. Between the clamping nut 280 and the grinding wheel 26 are sleeves 30:) of an external diameter approximately the same hat of the arbor to the ri ht, of the grinding wheel, whereby to add rigidity to the arbor.

Glue of the most important features of the nvciition. is a sizing tool, which ca u scs the g1 aiding to be interrupted inde .endent of the means for interrupting the cod when the w rk has progressed to a certain predetermined point. This tool, is a diamond pointed tru" tool. 285 similar to the trunw tool and is supported at such a height that. it will engage the grinding wheel at the point where the same comcs tangent to the work. The sizing tool is mounted in a sleeve 286 on a bracket 28? which has a. base 288 supported on and clamped to a block 289 which is set either on the base of the work holder or table which supports the work holder, Consequently the truing tool partakes of the feeding movement;- of the work and is moved constantly iicarer the grinding wheel as the feeding movement progresses. lt projects over the end. of the work in a similar man nor as does the truing tool 256, but is substantially at angles thereto. It is threaded into sleeve 286 and clamped in any adjusted position by a bolt 290 which acts to draw the pa ts of the split sleeve together. The tool adjusted so that it will travel across't iface of the grinding wheel after the wort been ground down almost to the finished size, say. to within two or three-thousandths of an inch. When thus traveling across the wheel it reduces the diameter thereof as fast as the feed progresses, and thus prevents it from cutting any farther into the Work. This sizing tool is of importance in that it fur"- nishes an automatic means for stopping the progress of the grinding at a safe point before the work has been brought down to the required. size, or before too much stock has been removed and is independent of wear on the wheel.

The range of work capable of being performed on this machine is not limited by the dimensions of the machine itself, for larger work pieces may be operated on than can be accommodated in the machine dimcn sioned and arranged as shown in the drawings, by elevating the brackets 81 carrying the cross slides on which the spindle beads are mounted. and elevating also the work holders. As the spindle head brackets are dctachably mounted on the slides 43 and .70, they may be disconnected and lifted, and rising blocks may be inserted beneath them, these blocks being clamped to the slides, and the brackets being clamped to the blocks. Similarly the bases of the work holders may be lifted from the bed, and rising blocks insorted under them. As the belts by which the grinder spindles are rotated pass above the slides, they intcrposc no impediment to the raising of the spindle heads, and consequent-ly do not limit. the amount. by which the capacity of the machine for larger work may beinci'eascd, The only limit; to such increase is the distance by which the cross teed carriage can be moved forward, and the distance by which the slides carrying the spindle beads may be moved to the roar.

I claimz l. A grinding machine comprising, in combination, a bed. means for reciprocating said bed. two grinder spindles overhanging said bed parallel to the direction of reciprocation thereof and approximately in line with each other, grinding wheels mounted on the adjacent. ends of said spindles and,

worlosiipporting means capable of holding dill'crent work pieces secured to said bed, the work pieces being thereby carried back and forth simullancousl), each in operative relation with one of said grinding wheels.

2. A grinding machine comprising, in combination, a bed, two grinder spindles extending toward one another from opposite directions, grinding wheels mounted on the adjacent qnds of said spindles, a work holder mquntcd bet-ween said wheels, and automatic mechanism for na-iprwating said holder in line with said spindles to carry the work held thereby buck and forth in simultaneous operative relation with both said wheels.

3. A grinding machine comprising the combination of a longitudinally reciprocatory bed, automatic mechanism for reciproeating said bed, spindle beads ro'ectin over said bed near the opposite on s t ereoi grinder spindles mounted in said heads and extending therefrom longitudinally of the bed toward one another, grinding wheels secured to the adjacent ends of said spindles, and a work holder mounted on said bed intermediate said grinding wheels and moved thereby so as to carry the work operatively past the grinding wheels in simultaneous contact vi-ith both wheels.

4;. A grinding machine comprising the combination of a longitudinally reciprocatory bed, spindle heads overhanging said bed near the opposite ends thereof, grinder spindles mounted in said heads and extending therefrom longitudinally of the bed toward one another, grinding wheels secured to the adjacent ends of said spindles. and means for supporting work pieces of differentcharacters on said bed, said pieces being caused by the reciprocntions of the bed to travel in operative relation with their rcspectivc grinding wheels simultaneously.

5. A grinding machine for internal work comprising the combination of a longitudinally reciproeatory bed, spindle heads overhanging said bed near the opposite ends thereof, grinder spindles mounted in said heads and extending therefrom longitudinally of the bed toward one another. grinding wheels secured to theadjaccnt ends of said spindles and adapted by their location to enter hollow work pieces, and means for siu iport-ing hollow work-pieces on the bed, whereby such pieces are carried back and forth overthcir respective grinding wheels.

(3. A grinding machine comprising the. combination of a longitudinally reciprocatory bed, spindle heads overhanging said bed near the opposite ends thereof, grinder spindles mounted in said heads and extending therefrom longitudinally of the bed to ward one another, grinriling wheels secured to the adjacent ends of said spindles; means on said bed adapted to support independently work pieces of dillerent shapes or sizes, each in operative relation with one of the grinding wheels. and automatic mecha nism for reciprocally driving said bed whereby ditl'erent operations .may be performed automatically at the same'time.

'7. A grinding machine comprising separated spindle supports, two spindles rotatably held in said supports and projecting oppositely therefrom toward one another,

grinding wheels mounted on the free ends of said spindles, and work-holding means intermediate said spindles and movable reciprocatively in a line parallel with the said spindles to carry work pieces back and forth in contact simultaneously with said grinding wheels, each being in contact with a separate wheel. I

8. A grinding machine comprising separated spindle supports, two spindles rotatably held in said supports and projecting oppositely therefrom, toward one another,

grinding wheels mounted on the free ends of said spindles, and work holding means intermediate said spindles; said work-holding means and spindles having relative back and 'forth longitudinal movements in a line parallel with said spindles, whereby the necessary relative travel of wheels and work is effected.

9. A' grinding machine comprising separated spindle supports. two spindles rotatably held in said supports and projecting oppositely therefrom toward one another. grinding wheels mounted on the free ends of said spindles, combined with a work holder between said grinding wheels rotatably mounted at its ends anddriven at its center, and a bed mounted to reciprocate in a line parallel with said spindles on which said work holder is mounted and by which it is caused to carry work back and forth in operative relation with the two wheels, said holder beingadjuslable about an axis perpendicular to its line of reciprocation for enabling tapcrd'work to be ground.

10. grinding machine for internal work comprising separated spindle supportsl two spindles rotatably held in said supports and projecting oppositely therefrom, toward one another, grinding wheels mounted on the tree ends of said spindles, work-holding means arranged and constructed to hold hollow work pieces in position to be entered by said wheels, and automatic mechanism for l'll'OlllN'lllg relative longitudinal reciprocating movement between the work-holding means and spindles respectively.

'11. A grim'ling machine comprising separ ted spindle supports, two spindles rotalaoly held in said supports and projecting oppositely therefrom, toward one another, grinding wheels mounted on the free ends of said spindles, combined with a tubular work holder in which work may be held in position to be acted on simultaneously by both grinding wheels, bearings inwhich said holder is rotarily mounted near its ends, a rotating driver for said holder between said bearings, and a bed by which said hearings are supported.

12. A grinding machinecomprising separated spindle supports, two spindles rotatably held in said supports and projecting oppositely therefrom, toward one ancither, grinding wheels mounted on the free ends of said spindles, a bed caused to reciprocate ,in the line of said spindles, and separate work holders mounted on said bed, each adapted to secure a work piece in position to be operated on by one of said wheels as said bed reciprocates.

13. A grinding machine comprising separated spindle supports, two spindles r tatablyv held in'said supports and project ing oppositely therefrom, toward one another, grinding wheels mounted on the free 

